1. Arrays r fixed in size and hence once we created an array we are not allowed to increase or decrease the size based on our requirement.
Collections are growable in nature and hence based on our requirement we can increase or decrease the size.
2. Memory point of view arrays are not recommended to use.
Memory point of view collections are recommended to use.
3. Performance point of view arrays are recommended to use.(Faster)
Performance point of view collections are not recommended to use.
4. Arrays can hold only homogeneous elements.
Collections can hold both homogeneous and heterogeneous elements.
5. Arrays can hold both primitives as well as objects.
Collections can hold only objects.
6. For any requirement, there is no ready method support compulsory programmer has to code explicitly.
For every requirement ready made method support is available. Being a programmer we have to know how to use those methods and we are not responsible to implement those.